Compilare: user.cpp: In function ‘bool distance(std::vector<int, std::allocator<int> >)’: user.cpp:21: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘bool valid(std::vector<int, std::allocator<int> >)’: user.cpp:28: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void normalize(std::vector<int, std::allocator<int> >&)’: user.cpp:36: warning: comparison between signed and unsigned integer expressions user.cpp:38: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void buildmat(std::vector<int, std::allocator<int> >&)’: user.cpp:61: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void mul(int (*)[255], int (*)[255])’: user.cpp:78: warning: unused variable ‘lim’ user.cpp: In function ‘int main()’: user.cpp:117: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:118: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:119: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result